| 1. |
- Bagni, Tommaso, et al.
(författare)
-
Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC
- 2024
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 34:5, s. 1-5
-
Tidskriftsartikel (refereegranskat)abstract
- A newly designed superconducting magnet of the Canted-Cosine-Theta (CCT) type was developed as a result of a collaboration between Swedish universities (Uppsala and Linneaus) and Swedish industries. This magnet was designed to function as a replacement of the present LHC orbit corrector magnets, which are approaching their end of life due to the radiation load. As a result, the new CCT magnet was developed to be more radiation tolerant and to constitute a one-to-one replacement to the currently installed version, which is a 1 m long 70 mm double aperture dipole magnet. The final magnet, which is currently under construction, will be tested at FREIA laboratory at Uppsala University and generate a magnetic field of 3.3 T and an integrated field of 2.8 Tm at about 85 A. To examine the magnet quench behavior and to identify a suitable quench protection system, the 3D electro-magnetic and thermal behavior of the coil was modeled using the RAT-Raccoon software. Based on the simulation results, a Metrosil varistor was selected to protect the magnet during the test. In this article, we report the results of the numerical analysis. The magnet model is equipped with a spot heater to initialize the quench and the temperature and voltages are monitored during the avalanche effect. The simulated current decay and the hot-spot temperature are analyzed with a focus on the impact of quench-back on the magnet protection.
|
|
| 2. |
- Bagni, T., et al.
(författare)
-
Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC
- 2024
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE. - 1051-8223 .- 1558-2515. ; 34:5
-
Tidskriftsartikel (refereegranskat)abstract
- A newly designed superconducting magnet of the Canted-Cosine-Theta (CCT) type was developed as a result of a collaboration between Swedish universities (Uppsala and Linneaus) and Swedish industries. This magnet was designed to function as a replacement of the present LHC orbit corrector magnets, which are approaching their end of life due to the radiation load. As a result, the new CCT magnet was developed to be more radiation tolerant and to constitute a one-to-one replacement to the currently installed version, which is a 1 m long 70 mm double aperture dipole magnet. The final magnet, which is currently under construction, will be tested at FREIA laboratory at Uppsala University and generate a magnetic field of 3.3 T and an integrated field of 2.8 Tm at about 85 A. To examine the magnet quench behavior and to identify a suitable quench protection system, the 3D electro-magnetic and thermal behavior of the coil was modeled using the RAT-Raccoon software. Based on the simulation results, a Metrosil varistor was selected to protect the magnet during the test. In this article, we report the results of the numerical analysis. The magnet model is equipped with a spot heater to initialize the quench and the temperature and voltages are monitored during the avalanche effect. The simulated current decay and the hot-spot temperature are analyzed with a focus on the impact of quench-back on the magnet protection.
|
|
| 3. |
- Barna, D., et al.
(författare)
-
Test Results of the First Wax-Impregnated Nb-Ti Canted Cosine Theta Septum Magnet “SuShi”
- 2024
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 34:5, s. 1-5
-
Tidskriftsartikel (refereegranskat)abstract
- In the framework of the future circular collider study, a new septum magnet concept (“SuShi”) has been developed, and a prototype was built at Wigner RCP, and tested at the FREIA facility of Uppsala University. The concept uses a canted cosine theta (CCT)-like superconducting magnet and a passive superconducting shield to create a zero-field and high-field region within its aperture. SuShi is the first CCT magnet with both of its winding layers simultaneously impregnated with wax. Details of the construction will be presented, with special emphasis on the wax impregnation procedure which deals with the ∼ 15% contraction of wax upon solidification. The empty magnet (no shield in its aperture) was powered without training to 450 A with a peak field of 3.64 T, corresponding to 80% of the short sample limit of the conductor along the load line. No quench or other anomaly was observed during the entire testing period. A clear onset of quench-back was observed above about 200 A.
|
|
| 4. |
- Barna, D., et al.
(författare)
-
Training-free performance of the wax-impregnated SuShi septum magnet
- 2024
-
Ingår i: Superconductors Science and Technology. - : Institute of Physics (IOP). - 0953-2048 .- 1361-6668. ; 37:4
-
Tidskriftsartikel (refereegranskat)abstract
- In the framework of the Future Circular Collider Study a new septum magnet concept, nicknamed 'SuShi' has been developed, and a prototype was built at Wigner Research Center for Physics, and tested at the FREIA facility of Uppsala University in April 2023. The concept uses a canted cosine theta (CCT)-like superconducting magnet and a passive superconducting shield to create a zero-field and high-field region within its aperture. SuShi is the first CCT magnet with both of its winding layers simultaneously impregnated with wax. This paper describes the first powering test of the empty magnet at 4.2 K, without the shield being inserted in its aperture. The performance of the magnet, including the observation of quench-back, estimation of hot-spot temperatures and the fraction of energy dissipated in the magnet are presented, and most interestingly the absence of any quench during the entire testing period is reported. Sushi reached its nominal +5% peak field of 3.64 T at 450 A, which corresponds to 80% of the calculated short sample limit along the load line, without training.
|
|
| 5. |
- Bhattacharyya, Anirban, et al.
(författare)
-
ESS RF Source and Spoke Cavity Test Plan
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes the test plan for the first high power RF source, ESS prototype double spoke cavity and ESS prototype cryomodule at the FREIA Laboratory.
|
|
| 6. |
- Goryashko, Vitaliy, et al.
(författare)
-
HIGH-PRECISION MEASUREMENTS OF THE QUALITY FACTOR OFSUPER CONDUCTING CAVITIES AT THE FREIA LABORATORY
- 2015
-
Konferensbidrag (refereegranskat)abstract
- The dependence of cavity quality factor Q0 on accelerating gradient gives insight into the intrinsic limit of RFsurface impedance that determines the cavity performance. In this paper we propose a high-precision method of measuringQ0 of SRF cavities. A common way to study the performance of an SRF cavity is to build an oscillator around it that is referred to as a self-excited loop. In the standard approach, by tuning the loop phase for a maximum field level in thecavity and measuring forward and reflected waves, one finds the cavity coupling. Then, performing a time-decay measurement and finding the total quality factor, one gets Q0. However, this approach suffers from a deficiency originating from a single data-point measurement of the reflection coefficient. In our method by varying the loop phase shift, one obtains amplitudes of the reflection coefficient of the cavity as a function of its phases. The complex reflection coefficient describes a perfect circle in polar coordinates. Fitting the overdetermined set of data to that circle allows more accurate calculation of Q0 via the least-squares procedure. The method has been tested at the FREIA Laboratory on two cavities from IPN Orsay: a single spoke and a prototype ESS double spoke.
|
|
| 7. |
- Goryashko, Vitaliy, 1982-, et al.
(författare)
-
Proposal for Design and Test of a 352 MHz Spoke RF Source
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- More than a dozen of spoke resonators prototypes (SSR, DSR, TSR) have been constructed and tested worldwide. None have accelerated beam until now and the ESS LINAC will be the first accelerator to operate with spoke cavities. Experience with other types of superconducting cavities indicates that high-power test is vital for reliable operation of the cavity in an accelerator. Although characteristics of a bare cavity can be obtained in a low-power test some important features of a `dressed' cavity like the electroacoustic stability and tuning system can be studied only in a high-power test stand. The ESS LINAC is a pulsed machine and the Lorentz detuning originating from the electromagnetic pressure on the cavity walls is expected to be strong. The Lorentz force along with the cavity sensitivity to mechanical excitations at some resonant frequencies may lead to self-sustained mechanical vibrations which make cavity operation dicult. Practical experience shows that increasing the boundary stiness will decrease the static Lorentz force detuning but not necessarily the dynamic one. Therefore, the FREIA group at Uppsala University is building a high-power test stand able to study performance of the ESS spoke cavity at high power. The RF test stand will be able to drive the cavity not only in the self-excitation mode but also with closed RF loop and fixed frequency. The later technique will be used to reproduce the shape of the cavity voltage pulse as it is expected to be in the cavity operating in the ESS LINAC such that the cavity tuning compensation system will be tested under realistic conditions.
|
|
| 8. |
- Junquera, Tomas, et al.
(författare)
-
Design of a New Horizontal Test Cryostat for Scrfcavities at the Uppsala University
- 2014
-
Ingår i: SRF2013: Proceedings of the 16th International Conference on RF Superconductivity. - 9783954501434 ; , s. 325-327
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- At Uppsala University, the FREIA facility for researchand development of new accelerators and associatedinstrumentation, is presently in construction. Associatedto a new Helium Liquefier, a Horizontal Test Cryostat willbe used for high power RF tests of completely equippedSC cavities. This paper presents the main characteristicsof the cryostat. Two types of cavities have beenconsidered for test purpose: SC elliptical cavities forfuture free electron lasers and SC cavities for highintensity proton accelerators. A special valve boxincluding a subcooling stage and power coupler coolingwith supercritical Helium supply have been designed, fortemperature operation ranging from 2 K to 4.2 K. Thisfacility will play an essential role in the development andtest of cavities, couplers and cryomodules for the ESSproject. High power RF sources will be installed in orderto allow unique and complete tests of spoke cavities andcryomodules at high nominal peak power.
|
|
| 9. |
- Li, Han, et al.
(författare)
-
Characterization of a beta=0.5 double spoke cavity with a fixed power coupler
- 2019
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 927, s. 63-69
-
Tidskriftsartikel (refereegranskat)abstract
- ESS, the European Spallation Source, will adopt a single family of double spoke cavities for accelerating the beam from the normal conducting section to the first family of the elliptical superconducting cavities. It will be the first double spoke cavities in the world to be commissioned for a high power proton accelerator. The first double spoke cavity for the ESS project was tested with high power in the HNOSS cryostat at Uppsala University. A pulse-mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involves a double-spoke superconducting cavity, a fixed fundamental power coupler, tuner, a low-level radiofrequency (LLRF) system and a high-power radiofrequency (RF) station. The test represents an important verification milestone before the module assembly. This cavity had unfortunately a high dynamic loss of 12W @ 9 MV/m, where potential causes for such a high value have been studied and corresponding suggestions are listed. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.
|
|
| 10. |
- Li, Han, et al.
(författare)
-
ESS Spoke Cavity Conditioning at FREIA
- 2017
-
Ingår i: Proceedings of IPAC2017. - 9783954501823 ; , s. 1074-1076
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The first ESS double spoke cavity installed with RF power coupler was tested in the HNOSS cryostat at the FREIA Laboratory. Power coupler and cavity conditioning have been optimized in order to reach high efficiency and high availability by reducing the time and effort of the overall conditioning process. Meanwhile, an optimal procedure for ESS conditioning is studied. This paper presents the study result and experience of the RF conditioning procedure for the first ESS double spoke cavity.
|
|
| 11. |
- Li, Han, et al.
(författare)
-
First High Power Test of the ESS Double Spoke Cavity
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The first double spoke cavity for ESS project was tested with high power in the HNOSS cryostat at FREIA Laboratory. This cavity is designed for 325.21MHz, a pulse mode with 14 Hz repetition rate, up to peak power of 360 kW. The qualification of the cavity package in a high power test, involved a spoke superconducting cavity, a fundamental power coupler, LLRF system and a RF station, represented an important verification before the module assembly. This report presents the test configuration, RF conditioning history and first high power performance of this cavity package.
|
|
| 12. |
- Li, Han, et al.
(författare)
-
First High Power Test of the ESS High Beta Elliptical Cavity package
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The first high-beta elliptical cavity for ESS project was tested with high power in the HNOSS cryostat at FREIA Laboratory. This cavity is designed for 704.42 MHz, a pulse mode with 14 Hz repetition rate, up to peak power of 1.5 MW. The qualification of the cavity package in a high power test, involved an elliptical superconducting cavity, a fundamental power coupler, cold tuning system, LLRF system and klystron system, represented an important verification before the module assembly. This report presents the test configuration, RF conditioning history and first high power performance of this cavity package.
|
|
| 13. |
- Li, Han, et al.
(författare)
-
High power testing of the first ESS Spoke cavity Package
- 2017
-
Ingår i: Proceedings of the 18<sup>th</sup> International Conference on RF Superconductivity. - 9783954501915
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The first double spoke cavity for the ESS project was tested with high power in the HNOSS cryostat at the FREIA Laboratory. This cavity is designed for 325.21MHz, pulsed mode with 14 Hz repetition rate, up to a peak power of 360 kW. The qualification of the cavity package in a horizontal test, involving a superconducting spoke cavity, a fundamental power coupler (FPC), LLRF system and RF station, represents an important verification before the module assembly. This paper presents the test configuration, RF conditioning history and first high power performance of this cavity.
|
|
| 14. |
- Li, Han, et al.
(författare)
-
RF Performance of the spoke prototype cryomodule for ESS
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The European spallation source (ESS), as a world-class high power proton accelerator facility, will be the first one to adopt 26 double spoke resonators (DSR) at its low energy section. As a new superconducting accelerating structure, these DSRs are therefore considered as a key technology and challenge of the whole project. They will be the first D SRs in the world to be commissionedfor a high power proton accelerator. As a milestone, the first DSR prototype cryomodule for ESS project was successfully tested at the FREIA Laboratory. In this qualification of the prototype cryomodule, the whole chain of RF station, RF distribution, fundamental power coupler (FPC), DSRs, cold tuning system (CTS) and low level radio frequency (LLRF) system, as well as the testing procedure have been verified on preparation for the industrialized cryomodules. Both cavities in the prototype cryomodule achieved nominal accelerating gradient, with the maximum gradient of 15 MV/m and 10.5 MV/m for cavity 1 and cavity 2 respectively. Based on the calorimetrical method, the dynamic heat load measurement showed that the cavity power consumption is around 0.5 W and therefore the intrinsic quality factor is consistent with the vertical test. This report presents the test configuration, RF conditioning history and first high power performance of this cryomodule.
|
|
| 15. |
- Li, Han, et al.
(författare)
-
RF test of ESS superconducting spoke cavities at Uppsala University
- 2016
-
Ingår i: Proceedings of IPAC2016. - 9783954501472 ; , s. 791-794
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The European Spallation Source (ESS) is an accelerator-driven neutron spallation source built in Sweden. It will deliver the first protons to a rotating tungsten target by 2019 and will reach the full 5 MW average beam power in the following years. The superconducting Spoke cavities are considered compact structures at low frequencies and having an excellent RF performance in both low and medium velocity regimes, therefore ESS will include a total of 26 double-spoke cavities. The testing of the double-spoke prototype cavity at high power has been conceded to Uppsala University, Sweden, where the Facility for Research Instrumentation and Accelerator development (FREIA) has been equipped with superconducting cavity test facility. A bare spoke cavity has been tested at the FREIA Laboratory with a self-exited loop at low power level to confirm its vertical test performance at IPNO. Similar test results as IPNO's previous test were obtained with FREIA system. In this paper we present the methods and preliminary study results of the cavity performance.
|
|
| 16. |
- Li, Han, et al.
(författare)
-
Test Characterization Of Superconducting Spoke Cavities At Uppsala University
- 2015
-
Konferensbidrag (refereegranskat)abstract
- As part of the development of the ESS spoke linac, the FREIA Laboratory at Uppsala University, Sweden, hasbeen equipped with a superconducting cavity test facility. The cryogenic tests of a single and double spoke cavitydeveloped by IPN Orsay have been performed in the new HNOSS horizontal cryostat system. The cavities areequipped with a low power input antenna and a pick-up antenna. Different measurement methods wereinvestigated to measure the RF signal coupling from thecavity. Results from the tests confirm the possibility to transport the cavities from France to Sweden without consequences. We present the methods and preliminary study results of the cavity performance.
|
|
| 17. |
- Olvegård, Maja, et al.
(författare)
-
PROGRESS AT THE FREIA LABORATORY
- 2015
-
Ingår i: Proceedings of IPAC'15. - JACoW : The Joint Accelerator Conferences Website.
-
Konferensbidrag (refereegranskat)abstract
- The FREIA Facility for Research Instrumentation and Accelerator Development at Uppsala University, Sweden, has reached the stage where the testing of superconducting cavities for the European Spallation Source (ESS) is starting. The new helium liquefaction plant has been commissioned and now supplies a custom-made, versatile horizontal cryostat, HNOSS, with liquid helium at up to 140 l/h. The cryostat has been designed and built to house up to two accelerating cavities, or, later on, other superconducting equipment such as magnets or crab cavities. A prototype cavity for the spoke section of the ESS linac will arrive mid 2015 for high-power testing in the horizontal cryostat. Two tetrode-based commercial RF power stations will deliver 400 kW peak power each, at 352 MHz, to the cavity through an RF distribution line developed at FREIA. In addition, significant progress has been made with in-house development of solid state amplifier modules and powercombiners for future use in particle accelerators. We report here on these and other ongoing activities at the FREIA laboratory.
|
|
| 18. |
- Pepitone, Kevin, Dr, 1988-, et al.
(författare)
-
First magnet operation on the cryogenic test stand Gersemi at FREIA
- 2021
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Gersemi cryogenic test bench, installed at FREIA laboratory at Uppsala University, was used for the first time in 2021 to power a superconducting magnet. As part of the HL-LHC program, this cryostat offers an operating temperature between 4.2K and 1.9K. Its satellite equipment such as power converters and the acquisition system allow two superconducting magnet coils to be powered up to 2 kA and provide magnet protection through a robust quench detection and two energy extraction units. This report describes Gersemi's first cryogenic operational experiment and the safety strategy to ensure magnet integrity during operation.
|
|
| 19. |
- Profatilova, Iaroslava, et al.
(författare)
-
ESS Double Spoke Cryomodule Testing : Report Compilation
- 2024
-
Rapport (populärvet., debatt m.m.)abstract
- This document compiles the test reports for all fourteen (14) ESS double-spoke cryomodules tested at FREIA. Each report covers both cryogenics and radio-frequency aspects of each test and is presented in sequential order by cryomodule.
|
|
| 20. |
- Ruber, Roger, et al.
(författare)
-
Accelerator development at the FREIA Laboratory
- 2021
-
Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:7
-
Tidskriftsartikel (refereegranskat)abstract
- The FREIA Laboratory at Uppsala University focuses on superconducting technology and accelerator development. It actively supports the development of the European Spallation Source, CERN, and MAX IV, among others. FREIA has developed test facilities for superconducting accelerator technology such as a double-cavity horizontal test cryostat, a vertical cryostat with a novel magnetic field compensation scheme, and a test stand for short cryomodules. Accelerating cavities have been tested in the horizontal cryostat, crab-cavities cavities in the vertical cryostat, and cryomodules for ESS on the cryomodule test stand. High power radio-frequency amplifier prototypes based on vacuum tube technology were developed for driving spoke cavities. Solid-state amplifiers and power combiners are under development for future projects. We present the status of the FREIA Laboratory complemented with results of recent projects and future prospects.
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Santiago-Kern, Rocio, et al.
(författare)
-
Cryogenic Performance of the Spoke Prototype Cryomodule for ESS
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of all the cryogenic tests performed on the prototype spoke cryomodule, which housed Romea (cavity 1) and Giulietta (cavity 2) with all their ancillary equipment, such as static and dynamic heat loads under different circumstances.
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Santiago-Kern, Rocio, et al.
(författare)
-
Gersemi tests with Dummy Cavity in Liquid Insert (Run 2)
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of the cryogenic tests performed on the vertical cryostat Gersemi with a dummy cavity connected to the liquid insert between the end of November and the beginning of December 2019.
|
|
| 28. |
- Santiago-Kern, Rocio
(författare)
-
Gersemi tests with the DQW Crab Cavity Niowave 001 at FREIA
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of the cryogenic tests performed on the vertical cryostat Gersemi with the DQW crab cavity Niowave 001 connected to the liquid insert from mid January to mid February 2023.
|
|
| 29. |
- Santiago Kern, Rocio, et al.
(författare)
-
Gersemi tests with the MCBRD Magnet at FREIA
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of the cryogenic tests performed on the vertical cryostat Gersemi with the dipole magnet MCBRD connected to the magnet insert between the end of March and the beginning of May 2022.
|
|
| 30. |
- Santiago-Kern, Rocio, et al.
(författare)
-
The Gersemi Vertical Cryostat at FREIA
- 2017
-
Ingår i: Cryogenics 2017. - 9782362150227
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- “Gersemi”, a vertical cryostat to test superconducting magnets and radio-frequency cavities at liquid helium temperatures, will be installed at FREIA Laboratory at Uppsala University, Sweden. With three independent inserts, the same cryostat can be used to test different superconducting equipment at low power: a “vacuum” insert for cavities equipped with a helium vessel, a “bath” insert for cavities (and other equipment) without a helium vessel and a “lambda-plate” insert for magnet testing. Each insert has been designed to be as versatile as possible, making the available space inside the cryostat the main constraint for equipment testing. The cryostat will have an internal diameter of 1.1 m and 4.7 m total height. For magnet testing, “Gersemi” will be able to handle superconducting magnets with a stored energy up to 340 kJ. A valve box to direct the cryogens, a reheater for warming up the output gases and a control system complete the setup."Gersemi" vertical cryostat is connected to a helium liquefier and recovery system, and in parallel to an existing horizontal cryostat for testing superconducting equipment already operational at FREIA Laboratory.
|
|
| 31. |
- Wedberg, Rolf, 1947-, et al.
(författare)
-
Power Supplies for Tetrode High Power Amplfiers at FREIA : ESS TDR Contribution
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper select the topology of the power supplies to the RF power amplifier to one spoke cavity to be tested at FREIA Uppsala University.The power supplies are thought to fulfill the requirements of ESS in Lund.The amplifiers pulsed operation will have a strong impact of the choice of topology. The RF amplifier will have two tetrodes in the final stage.The anode power supply is studied for different topologies and number of anodes to supply.Storing the energy for pulse current to the anodes at high voltage or at low voltage is considered.The short circuit protection can be with a crowbar or a series switch. The series switch is selected for reasons of short interrupts in case of temporary short circuits.The grid and filament supplies are thought to be standard of the shelf power supplies.Cost estimate and comments on maintenance in the end of the paper.
|
|
| 32. |
- Yogi, Rutambhara, 1968-, et al.
(författare)
-
Selection of RF Power Source and Distribution Scheme at 352 MHz for Spoke Cavities at ESS and FREIA
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The report describes selection of RF power source and distribution scheme for spoke cavities at ESS and FREIA. The European Spallation Source (ESS) is the world’s most powerful neutron source, which contain 36 superconducting spoke cavities at 352MHz and provide power of 0.5MW to the beam. The baseline for the RF system is a point-to-point generation and distribution from a single source to a single accelerating cavity.The RF system that has to generate this power and distribute it to the accelerating cavities, is a main resource driver for linear accelerators in form of investment, operation and maintenance. Therefore the technical alternatives are compared to minimize capital and running cost of the accelerator, without compromising its reliability. At 352 MHz and 350 kW RF power output, tetrode amplifiers are selected because of their advantages of being cheap, reliable, simple and efficient as compared to the other RF power amplifiers. The tetrodes, due to their low gain, need a pre-driver. The solid state amplifier technology is selected as a pre-driver due to its simplicity, reliability and efficiency. Half height aluminum WR2300 wave guides shall be used for RF distribution. This solution makes it possible to discard the circulator from the RF distribution chain, thus improving system efficiency.
|
|
| 33. |
|
|
